Bed frames are used to support a box spring and mattress several inches off the floor, and are commonly mounted upon casters at the four corners and optionally at intermediate points of the frame. Typically the bed frame consists of a plurality of generally L-shaped side and cross frame members detachably secured to one another for supporting the mattress and box spring unit between a foot board and head board. In the industry, the frame members are often made from recycled railroad rail steel which is heated, re-shaped and processed into the L-shaped configuration. This recycled steel has very high carbon content and high strength as compared to conventional structural component materials. In the prior art, the generally orthogonal frame members are connected at the intersections by brackets which are attached to the ends of the frame members. For example, U.S. Pat. No. 3,683,429 describes a bed frame wherein several bracket pieces are attached to both of the intersecting frame members. Frames are supported by casters held by caster mounting brackets which are attached to the frame members. The casters are held by brackets which are attached to the frame members. The steel from which such brackets are made is of significantly lower strength than that of the frame members. Thus, the strength of the frame members is not utilized at the intersections, where high load and moment forces occur. Also, the brackets represent a number of parts which must be fabricated and separately attached to the frame members. Some frame designs which include a center rail within a rectangular frame require as many as 22 or more bracket pieces and 44 to 48 or more fasteners such as rivets.
In some prior art bed frames, the box spring supporting surfaces of the intersecting frame members are not flush, i.e., not in the same plane. This occurs as a result of the complex bracket assemblies used to form the intersections, particularly those which rely on a tapered wedge type connection. Consequently, the wooden frame of a box spring and the mattress will warp and sag when placed on such frames, especially in the center.
A bed frame which utilizes the substantial strength of the frame members as an integral component of the frame intersections, which eliminates many bracket pieces, and which provides a truly flush support surface is described in U.S. Pat. No. 6,397,412. A bed frame structure, as described in the previously mentioned patent, has interlocking members and flush rail support surfaces and is shown in FIGS. 1-3 (PRIOR ART). Flush bed frame 10 utilizes the terminal ends of rail member 12 as an integral structural connection to universal unibody caster mount 14 at the intersection of rail member 12 and caster mount 14. Slot 16 in caster mount 14 is configured to accept leg 18 of rail member 12 to precisely align the horizontal flanges of the intersecting rails to provide a truly flush support surface for a mattress box spring. No bracketry is required at the ends of rail member 12 for connection to caster mount 14, as slot 16 in caster mount 14 accepts a portion of rail member 12, creating a mechanical connection using the geometry of member 12 and caster mount 14. The caster mounts are of a universal configuration at each rail intersection of the flush bed frame. The rail-accepting slots in the caster mounts are configured to accept and receive one or two rail flanges.
One deficiency of the bracket-less connection of the design of the flush bed frame is the rail member easily separates from the caster mount when an upward force is applied to the rail member while the bed is in its standard position on the floor. The rail member also easily separates from the castor mount when the bed frame is rotated sideways or upside-down, as gravity forces the rail member apart from the castor mount.
Bed frames are often rotated sideways during the process of moving the bed frame to a new location to maneuver the frame such that it fits through doorways. Often when the bed frame is flipped the rail member separates from the castor mount, falling radially outwards towards the floor. The falling rail member can cause damage to the walls or floor of the house as it falls, as well as pose a safety hazard to any person standing in its path during the fall. A cap or other means capable of securing the interconnected linear members of the flush frame is not provided by the Prior Art.
Therefore, as shown in the Prior Art, there is still a need for a device to secure the bracket-less connection of the rail member to the castor mount of the flush bed frame design so as the members do not easily separate.